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91
Arctic sea ice / Re: The 2017 melting season
« Last post by VeliAlbertKallio on August 16, 2017, 06:25:31 PM »
The reduction in compressive strength is crucial during warm winter and subsequent spring like 2016/2017 winter. In addition, pulverization itself leads to further weakening as sides and the ice fractures sitting in water leak in heat from sides and thus this a positive ice pulverization feedback.

I suspect, PIOMAS underestimates importance of switchover from 2D melt to 3D melt - as the sides have become far greater to add "side melt" to the "bottom melt". Notably, bottom melt and side melt continues weeks after surface melting has ended and I suspect PIOMAS isn't geared to see into 2D bottom melt becoming a 3D event. Ice may continue to soften too - keeping it fragile.

<snip>
<snip>the variation in mechanical strength with temperature https://link.springer.com/article/10.1023%2FA%3A1021134128038 <snip>
92
Arctic sea ice / Re: The 2017 melting season
« Last post by VeliAlbertKallio on August 16, 2017, 06:06:48 PM »
The rear-end (Pacific side) is far from the North Pole. Around the Bering end of the sea, the sun appears early but the 24-hour sunshine season is least pronounced. At NP midsummer insolation is the most intense, but very brief. So far, the North Pole's ice misses strongest sun way before surface melting starts. The cooling arrives there first and ice movement is most constricted - quite the opposite to the most extreme southern reaches around the Bering Straits end. Thus this may not be extrapolated indefinitely towards NP: "Findings from this study show that the feedback effect triggered by early-season divergent ice motion plays a key role in the seasonal evolution and interannual variation of sea ice retreat in the Pacific Arctic, particularly since the early 2000s."
This recent interesting paper, published online yesterday, may help further our understanding of the melting season a bit.
93
The rest / Re: The Trump Presidency (was "Presidential Poll")
« Last post by TerryM on August 16, 2017, 06:04:49 PM »
I was ranting about Trump and white trash... and now Trump needs to confirm it!

Which reminds me of the first modern edition I saw of Hitler's book Mein Kampf (quite a lousy if not ridiculous book, my Grandpa left me one). It was an english translation, on the small bookshelf of a high school buddy in New Jersey, 1982.


Mine is a 1,003 page annotated English edition from 1939 that proudly claims not to have paid the nefarious author a nickel. Plenty of maps and pages of refutations per paragraph of statement.
Gifted to my father from my mother on xmas of 39, while he was still her chief chemist.


What a strange gift to an employee, a prospective mate, or a friend at the tail end of a long depression. I never knew either parent as having strong political feelings and was sometimes embarrassed by my mothers anti-Semitic bent. She fondly remembered Al Jolson as a family friend & neighbor, but would complain of sharp business dealings as just too "Jewy, Jewy, Jewy".
Perhaps she was just a product of her time.


Terry
94
Arctic sea ice / Re: The 2017 melting season
« Last post by oren on August 16, 2017, 05:54:31 PM »
What's the mechanism for extent loss all the way into October? It'll have been below freezing over most the Arctic for a whole month by then.

Some spots will continue to melt, sure, but higher latitudes will be freezing up.

Yep, in fact, one could argue that the high CAB freezing season typically starts at the end of August (depending on weather).

Question. What impact might so much open water appearing across the high CAB have in delaying this? Decreased albedo, ocean warming in those polynyas. How much does concentration have to drop before the coupling between the ice and 2m air temperatures starts to break down?
2016 was the first year that had widespread melting in the "high CAB", more noticeable in area stats than in extent numbers. On Sep 10th and Sep 11th the whole center refroze, while extent continued dropping for a few more days thanks to the periphery.
In order to delay refreezing I believe the whole area has to be clear of ice for at least a few days (weeks?) to allow mixing of the cold fresh water layer.
This year looks quite similar to 2016 around the pole. I therefore expect this year to have an early refreeze as well, before Sep 15th, unless some major compaction event magically brings all the ice to the center and clears the periphery.
95
Consequences / Re: 2017 ENSO
« Last post by AbruptSLR on August 16, 2017, 05:22:41 PM »
ASLR, todays figure from NOAA wrt OHC shows a skydive downward.
snip
Second, the PDO value for July was a meager +0,10 so the long positive streak is still there but it remains to see if it will survive August too.

The attached images (first of Cowan's Nino 3.4 issued today & the second of the NOAA Nino 3.4 forecast, also issued today), concur that we are rapidly moving to the cool side of neutral ENSO conditions.
96
The rest / Re: The Trump Presidency (was "Presidential Poll")
« Last post by Martin Gisser on August 16, 2017, 05:11:44 PM »
So, grab more popcorn.
Slowly methinks 2016/17/18 is the wreckage not of the D, but of the R party... and now, moral wreckage reckoning (who was Abe Lincoln?)... some Rs can't stand it anymore.

Maybe the GOP isn't yet completely rotten.
97
Policy and solutions / Re: Geoengineering, another rush for money?
« Last post by AbruptSLR on August 16, 2017, 05:06:21 PM »
Given the short period that most of the proposed geo-engineering aerosol particles will stay in the atmosphere, there will most probably be proposals for short-duration/large-scale tests. Each time extending the period of the test to see the effects. Any bad effects, the test stops and the particles in the atmosphere are flushed out within a few weeks.

Add promises of food aid etc. and it does look like a viable option. Not one I actually want to see, but given the political realities quite likely at some point.


While I concur with you that: (a) decision makers will find it irresistible to deploy some limited form of solar geoengineering; and (b) that currently we are most likely too far from any major tipping point for a limited deployment of solar geoengineering to do irreversible damage to the climate state.  That said, in the coming decades we will move from a CO₂-eq of over 521 ppm to something closure to the 680 ppm experience during the last equable climate, and as the two following reposts indicate, it is conceivable that the perturbation from a limited solar engineering deployment (say circa 2045 to 2050) might flip the NH atmosphere into an equable pattern:

First repost:
"I note that the first attached image shows how the atmosphere can abruptly bifurcate from our current saddle-node into an equable atmospheric pattern; while the following reference (and the associated second attached image) indicate that such a bifurcation could occur as soon as the CO2-equiv concentration reaches about 680ppm.  I note that our current CO2-equiv well exceeds 520ppm.  Furthermore, if Hansen's ice-climate feedback due to the possible collapse of the WAIS were to occur in the next few decades then we might bifurcate into an equable climate pattern sooner rather than later (which would be stupid for us to allow to happen).

Jagniecki,Elliot A. et al. (2015), "Eocene atmospheric CO2from the nahcolite proxy", Geology, http://dx.doi.org/10.1130/G36886.1


http://geology.gsapubs.org/content/early/2015/10/23/G36886.1

ftp://rock.geosociety.org/pub/reposit/2015/2015357.pdf

Edit: For those who do not know, it is easier to flip the northern hemisphere into an equable pattern (than the southern hemisphere), which is exactly what a collapse of the WAIS would do, due to the bipolar seesaw effect."

Second repost:
"The linked reference demonstrates for systems that can change abruptly, like Earth's climate (see the first attached image), why it is a bad idea for denialists to point at the large-noise in Earth's climate record to feel comfortable in the Holocene saddle-node that we have been resting in, as the second attached image shows that these large-noise fluctuations can kick us out of our comfortable saddle-node sooner, rather than later.

Corentin Herbert, and Freddy Bouchet (2017), "Predictability of escape for a stochastic saddle-node bifurcation: when rare events are typical", arXiv:1703.01450v1

https://arxiv.org/pdf/1703.01450.pdf

Abstract: "Transitions between multiple stable states of nonlinear systems are ubiquitous in physics, chemistry, and beyond. Two types of behaviors are usually seen as mutually exclusive: unpredictable noise-induced transitions and predictable bifurcations of the underlying vector field. Here, we report a new situation, corresponding to a fluctuating system approaching a bifurcation, where both effects collaborate. We show that the problem can be reduced to a single control parameter governing the competition between deterministic and stochastic effects. Two asymptotic regimes are identified: when the control parameter is small (e.g. small noise), deviations from the deterministic case are well described by the Freidlin-Wentzell theory. In particular, escapes over the potential barrier are very rare events. When the parameter is large (e.g. large noise), such events become typical. Unlike pure noise-induced transitions, the distribution of the escape time is peaked around a value which is asymptotically predicted by an adiabatic approximation. We show that the two regimes are characterized by qualitatively different reacting trajectories, with algebraic and exponential divergence, respectively."

Extract: "These results open new prospects for the analysis of time series exhibiting abrupt transitions such as those encountered in climate dynamics.""
98
Permafrost / Re: Arctic Methane Release
« Last post by Thomas Barlow on August 16, 2017, 04:56:46 PM »
That paper has been debunked repeatedly.
No it has not been debunked. Show your evidence please (not your non-peer-reviewed opinion)

They are discussing SLOW methane seeps deeper than 100 meters.
So now you are discussing what the paper shows, just after you said it was debunked.

Methane released from the ESAS does not interact with the water column but is released directly to the atmosphere. It only takes a few minutes to reach the surface.
That's not the point. Try reading the paper. Or should I explain it again?

Second, they avoided discussing the seasonality of the plankton blooms, whereas, the methane is released year round.
They did discuss the seasonality. Try reading the paper.
And again, not the point of the paper.

the rise in atmospheric methane concentrations in the Arctic is accelerating.
It doesn't say the methane would not be released. Try reading the paper.

Pohlman and Ruppel are petroleum geologists who work for the USGS gas hydrate project, promoting methane hydrate as an energy source in conjunction with the Oil and Gas industry.
I thought you just explained what the paper proves. Now you are saying it is fake-science. Make up your mind.
Besides, people quote USGS all the time here. I guess we'll have to ban NASA and NOAH being discussed as well?
Show your evidence for such outrageous claims about being in-league "with oil and gas industry".

Ruppel has been at the forefront of the methane hydrate disinformation campaign, attacking any papers suggesting methane hydrates are unsafe to extract, or may pose a danger to the environment.     
Show your evidence of such attacks by Ruppel please.
Besides, methane is safe to extract in and of itself, which I'm guessing is the point, but you didn't show the evidence so I don't know what Ruppel would be referring to.
The extraction methods may be unsafe.
But we don't need methane.

The conclusions in their paper is absolute nonsense.
You sound important.

As for the other paper, yes, methanatrophs evolved in the subglacial lakes as there is no sunlight to provide energy.  Duh.

You don't understand that paper either. Try reading it.
""We conclude that aerobic methanotrophy may mitigate the release of methane to the atmosphere upon subglacial water drainage to ice sheet margins and during periods of deglaciation.""

(PS. Condescension - arrogantly saying "duh" to people - is not appropriate here.)

99
The rest / Re: The Trump Presidency (was "Presidential Poll")
« Last post by Martin Gisser on August 16, 2017, 04:49:32 PM »
Michael Moore's recent best:
https://www.commondreams.org/news/2017/08/15/michael-moore-dont-lose-sight-horror-trump-inflicts-every-single-day
(One goodie at the beginning about the rise of U.S. Nazis late 1970ies/1980ies in Michigan. Seems my NJ Mein Kampf buddy back then was as avantgarde as he pretended.)

---------------------
Apropos MSNBC's "The Last Word With Lawrence O'Donnell". The other hardcore show  ;) before is Rachel Maddow. From both last night:

Trump remarks on racist rally force moral reckoning for GOP:
http://player.theplatform.com/p/7wvmTC/MSNBCEmbeddedOffSite?guid=n_maddow_dschmidt_170815

Could Trump's comments lead to a GOP presidential primary?
http://player.theplatform.com/p/7wvmTC/MSNBCEmbeddedOffSite?guid=n_lw_bprimary_170815

First, from Rachels interview with a seasoned GOP strategist, this could well be a breakpoint for what is left of a serious GOP.
Second, at the end of a O'Donnell interview with yet another GOPer, there is serious party rebellion in the making. Tears almost flowing in another interview.
100
Antarctica / Re: Antarctic Tectonics
« Last post by AbruptSLR on August 16, 2017, 04:46:14 PM »
I'm not sure if anyone has produced a map where the ice thickness has been converted into base elevation of the continent.

As a public service, I re-post the attached image showing what Antarctica might look like if all the ice were removed and all the isostatic rebound had already occurred.  When compared to the map in Reply #81, clearly, this rebound could contribute meaningfully to sea level rise in the future.
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